1. Field of the Invention
The invention relates to aqueous dispersions of organosilicon compounds, the preparation thereof and the use thereof, in particular for the hydrophobing impregnation and mass hydrophobing of mineral and organic building materials.
2. Background Art
Silanes and siloxanes have long been used for the production of structures, for example in the form of solutions of silanes in organic solvents, as described, for example, in DE-A 1069057. However, for cost reasons as well as health hazards and handling of organic solvents with the associated environmental pollution associated with them, such solvent-borne compositions are disadvantageous.
Aqueous formulations based on alkylalkoxysilanes and alkylalkoxysiloxanes are known. EP-A 234 024 describes silane emulsions comprising nonionic emulsifiers which have an HLB value of from 4 to 15. According to EP-A 340 816, the stability of these compositions is improved by the addition of buffer salts. EP-A 631 999 describes aqueous formulations based on alkylalkoxysilanes which contain cationic emulsifiers. According to WO-A 199516752 and EP-A 907 622, amine soaps are said to be suitable in particular for the preparation of silane/siloxane emulsions. WO-A 199522580 describes a series of further cationic emulsifiers in silane/siloxane emulsions. According to EP-A 1 147 072, the stability of silane/siloxane emulsions is particularly good when ionic emulsifiers are used in combination with nonionic emulsifiers which have an HLB value of less than 11.
Nevertheless, the aqueous compositions prepared according to the prior art do not always have the desired stability and efficiency.